Presently we have built board and on inserting the 12 AC AC 1amp adapter the "on" LED does not light and after a few minutes the adapter burns out and no further current sent from adapter (£13!)
I obviously need to check the polarity (some are "film and ?dont have polarity?) and function of the capacitors and will remove them from the board to do this. I think we also need to take off the ICs and get new ones with cradles to avoid burning them up with solder heat.
If this doesnt work what would be the next step?
I keep telling my son this is science not Harry Potter wizardry and applying patience and logic should sort it out but we need a little bit of kind support!
Many thanks for anything the Forum can offer. We are not giving up!
(is burning out of the adapter consistent with dud or reversed polarity capacitor?)
Regards to all
1. The most likely way to get a short circuit is by an accidental solder bridge between adjacent tracks, or adjacent pins on the ICs.
2. Look for ICs inserted the wrong way round (very easy to do this!) - did you notice any getting hot before the adapter burnt out?
3. Components like diodes, transistors and electrolytic capacitors do not take kindly to reversed polarity. Reversed electrolytics can short (I remember being in a lab when a large one blew up like a bomb - tiny flakes of aluminium floated down like snow!) Make sure that they all have been inserted correctly - the layout diagram should indicate the polarity of each. Low value capacitors and fixed resistors are not polarised and can be inserted either way round.
Hope this helps